1. Technical Field
The disclosed embodiments relate in general to a 2D (two-dimensional)/3D (three-dimensional) switchable display, and more particularly to a 2D/3D switchable parallax barrier display with a low noise driving scheme.
2. Description of the Related Art
Autostereoscopic displays, also known as “Naked eye 3D display”, are able to provide binocular depth perception without the hindrance of specialized headgear or filter/shutter glasses. The naked eye 3D display technology has been developed for many years to provide stereoscopic vision by fooling the human brain, so that a 2D medium can display a 3D image by providing a stereo parallax view for the user.
Naked eye 3D displays have been demonstrated using a range of optical elements in combination with an LCD including parallax barrier technology and lenticular optic technology to provide stereoscopic vision. Generally, the parallax barrier has optical apertures aligned with columns of LCD pixels, and the lenticular optics has cylindrical lenses aligned with columns of LCD pixels. A parallax barrier is an electro optic panel with fine and vertical strips that are placed at a regular spacing, in front or rear of a colored LCD. FIG. 1 is a conventional 2D/3D switchable display with parallax barrier in front of display module. The 2D/3D switchable display 1 includes a backlight system 11, a display module 13 on the backlight system 11, a parallax barrier 15 above the display module 13, the polarizers 16a and 16b respectively on two sides of the display module 13, and polarizer 16c on the parallax barrier 15. The parallax barrier 15 having fine opaque strips separates the light pathway of spatial images into images for left eye and right eye to perceive 3D images. Users can see the left eye image/right eye image while the opaque stripes would block the right eye/left eye in the three-dimensional display mode. A touch sensor could be further integrated into the 2D/3D switchable display 1 by coupling a sensing electrode (not shown) on the parallax barrier 15, to making a 2D/3D display with touch screen.
FIG. 2 illustrates a 3D-mode driving scheme of the parallax barrier of a conventional normally-white LCD The parallax barrier (15 of FIG. 1) is a LCD panel comprising a LC layer 156 sandwiched between the bottom substrate and the top substrate, respectively having a bottom electrode 152 and a top electrode 154 coupled to different voltage sources. Typically, one of the bottom electrode 152 and the top electrode 154 is applied with a common voltage (i.e. 0V) while the other is applied with alternating voltages such as −5V and +5V. However, alternating voltage of the bottom electrode 152 induces voltage fluctuations (dotted-circled) on the top electrode 154. The voltage fluctuations would be a noise for the touch screen, which influences a performance of capacitive touch screen combined or integrated with the 3D display. To eliminate the influences with suppressing the voltage fluctuation, reducing a wiring resistance Rw of the top electrode 154 to coupling to ground (0V), shown in FIG. 2, is one of the solutions. However, a conductivity of transparent material of LC driving (i.e. ITO) complicates this countermeasure because it has relatively higher conductivity than metals like copper, aluminum and so on.